1. Field of the Invention
This invention pertains to rigid polyurethane foams containing alkylene oxide adducts of alkanolamines.
2. Description of the Prior Art
U.S. Pat. No. 4,438,235 teaches the use of tertiary alkanolamines for the preparation of non-cellular polyurethanes. U.S. Pat. No. 4,434,277 teaches the preparation of polyurethanes employing the reaction product of an aldehyde, phenol, and alkanolamine. U.S. Pat. No. 4,374,209 teaches the preparation of a polymer-modified polyol wherein an alkanolamine is polymerized with an organic polyisocyanate in the presence of a polyol.
This application relates to rigid polyurethane foams which have good K-factor properties and low smoke density properties. The foams are prepared by mixing a polyoxyalkylene polyether polyol other than one derived from an alkanolamine with an alkylene oxide adduct of an alkanolamine. The mixture is reacted with an organic polyisocyanate to form the polyurethane foam. The prior art does not disclose this combination of ingredients or the significance of the combination.